Conventionally, in some cases, rotating machines are controlled taking into account an electric power balance. For example, Patent Literature 1 discloses a technique related to a motive power output apparatus, a control method therefor, and an automobile, in which available electric power Pv that can be supplied to a motor MG2 is set by adding electric power generated by a motor MG1 to a battery output limit, and an engine 22 is started by driving the motor MG2 within the range of the available electric power Pv.